<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!-- 行内属性相当于给的都是字符串 -->
    <!-- 你相当于给 checked = 'false' -->
    <!-- 而 'false'其实是true -->
    <!-- 只有0、null、undefined、NaN、空字符串是false，其他都是true -->
    <input checked="bfdsjhfbvdsjkhfbvdsjlb" type="checkbox">

</body>
</html>